Soundwave doesn't say much, preferring to gather the intelligence that Megatron and Starscream use in their attempts to defeat the Autobots and conquer Earth. Possessing the ability to tap into and record any form of electronic transmission, Soundwave is a "fly on the wall" almost anywhere (except the Autobot's secret base). While not as physically formidable as the other Decepticons, Soundwave's telescoping "tentacles" have a long reach and whipping force that can snap through concrete.
A 15-year-old exchange student from Japan, Miko is fully absorbed into American pop culture. She's a free spirit who dresses in exuberant punk clothes and doesn't care what people think or say about her. It's only natural that the one with the interest in "speed metal" would instantly bond with Bulkhead, the Autobot who's the most "heavy metal." Miko is a fearless thrill-seeker, and often gets the Teens into dangerous situations, then improvises crazy solutions that only complicate matters.
A high school freshman, Raf is quiet, shy, and often the most frightened by the dangerous situations presented by the Teens' involvement with the Autobots. However, that all disappears the moment Raf spies any form of software-driven technology; he becomes instantly engaged and enters "the zone." Raf's savantlike prowess with computers might also be why he's the only human who unerringly understands his Autobot partner, Bumblebee, and often serves as his translator.
Starscream is Megatron's right-hand man, and a fearsome opponent who likes sneak attacks over direct confrontation. Because ambush is his specialty, whether from the sky, underground, or in disguise, Starscream's truly the most deceptive of all the Decepticons. He also happens to be a master strategist, which is why Megatron keeps him around. Starscream cowers before his general with false sincerity; he's impatiently waiting for the moment he can overthrow his leader and command the Decepticons.
Sixteen-year-old "Jack" lives with his mother and spends most afternoons working the drive-thru window at the local burger joint in order to save money for his first motorcycle-that is, until Arcee becomes his guardian Autobot! Suddenly, Jack gets a killer bike and big sister rolled into one. Jack often assumes a leadership role among the Teens, and is the voice of reason, practicality, and safety, except when he wants to impress a girl; in which case, all of that goes right out the window.
Though she doesn't possess the bulk of the other Autobots, Arcee can still kick Decepticon butt. She's sleek, fast, and as agile as a ninja. Arcee is self-possessed and sultry, a woman of few words-none of which are wasted. She and Optimus Prime share a deep understanding and respect for each other. Optimus also knows that, as the least "flawed" Autobot, Arcee's the most reliable. Arcee wasn't thrilled when assigned to Jack, but she comes to respect him and think of him as a partner.
Engineer, scientist, and medic, Ratchet repairs busted limbs and gears when needed, designs weapons and technology, and spends time brainstorming ways of getting the most from less and less Energon. Ratchet knows how to read Optimus Prime better than anyone. Though constantly questioning the need to risk their Autobot necks to protect humans (let alone sheltering some of them in their secret base), Ratchet secretly admires their contributions (especially Raf's) to the Autobot cause.
Leader of the Decepticons, Megatron is the most sinister and deadly of all the Transformers, both in terms of physical power and ruthlessness. Megatron is highly skilled with a fearsome arsenal of weapons. He's a cold-blooded warrior who shows no mercy. He is obsessed with defeating Optimus Prime, and detests Optimus's aim to protect the pathetic little pieces of flesh that run rampant over Earth. Megatron vows to defeat the remaining Autobots and take over the planet.
Embodying terrific brute strength, massive Bulkhead often gives the Autobots the edge in their battle with the Decepticons. But he proves to be a sensitive soul once he becomes joined at the hip with Miko. Because he's keenly aware of the "fragility" of humans, particularly in relation to his massive form, Bulkhead is paranoid about harming his tiny human companion. Miko quickly forces Bulkhead to loosen up, though. Chances are, if Bulkhead did something wrong, it's because she egged him on.
Bumblebee is eager to please and has a tendency to act without thinking. Because he has been on Earth longer than the other Transformers, he's the one who most identifies with the humans. Though prone to making mistakes, Bumblebee takes the responsibility of protecting Raf seriously-not only because he cares for his young cohort, but because he wants to excel in his assigned duty from Optimus Prime. Bumblebee speaks in bleeps and blurts as his vocal chords were damaged on Cybertron.
Leader, father figure, and strategist, Optimus Prime is like an Arthurian knight in blue and red armor. He was chosen by fate to protect the human race, in addition to rallying the remains of his own. Optimus feels responsible for every human injured, building damaged, or tree uprooted during the Autobots' transplanted war with the Decepticons. Optimus has a gravitas about him, which comes with surviving past wars and carrying the weight of Cybertron and Earth on his shoulders.